ia64.c (ia64_expand_atomic_op): Only use fetchadd{4,8}.acq instruction if CODE is PLUS or MINUS...

	* config/ia64/ia64.c (ia64_expand_atomic_op): Only use
	fetchadd{4,8}.acq instruction if CODE is PLUS or MINUS, for MINUS
	negate VAL.

From-SVN: r107703

gcc/ChangeLog

+2005-11-30  Jakub Jelinek  <jakub@redhat.com>
+
+	* config/ia64/ia64.c (ia64_expand_atomic_op): Only use
+	fetchadd{4,8}.acq instruction if CODE is PLUS or MINUS, for MINUS
+	negate VAL.
+
 2005-11-30  Paolo Bonzini  <bonzini@gnu.org>
 
 	* simplify-rtx.c (simplify_plus_minus): Remove final parameter.

gcc/config/ia64/ia64.c

@@ -2039,8 +2039,13 @@ ia64_expand_atomic_op (enum rtx_code code, rtx mem, rtx val,
   enum insn_code icode;
 
   /* Special case for using fetchadd.  */
-  if ((mode == SImode || mode == DImode) && fetchadd_operand (val, mode))
+  if ((mode == SImode || mode == DImode)
+      && (code == PLUS || code == MINUS)
+      && fetchadd_operand (val, mode))
     {
+      if (code == MINUS)
+	val = GEN_INT (-INTVAL (val));
+
       if (!old_dst)
         old_dst = gen_reg_rtx (mode);